The present invention relates generally to the field of methods of use of laser surgical probes. More specifically, the present invention relates to use of laser surgical probes in which laser energy is output generally transversely relative to the laser energy input to the probe.
Surgical techniques making use of laser technology have been developed for a variety procedures. However, the usefulness of standard surgical laser probes is limited in many of these procedures, such as where the surgeon must operate within a tightly confined body cavity or lumen, or where the area requiring laser treatment is accessible only around a tight corner.
One type of surgery which has heretofore not employed laser technology involves anterior capsulotomies. In ophthalmic surgery, it is frequently necessary to perform these procedures in order to expose a portion of the lens underlying the anterior capsule. One example where anterior capsulotomies are useful is where a surgeon desires to remove all or part of the natural lens for replacement with an intraocular lens (IOL).
A number of techniques for anterior capsulotomy have been developed, many of which can be classified as xe2x80x9ccan openerxe2x80x9d techniques, in which small scores are first placed around the region of the anterior capsule to be removed. These scores can be made by any of a variety of techniques, including the use of a needle, vibrating needle, or photodisruptive laser. After scoring, the surgeon tears between each of the scores to create a serrated capsular margin.
A disadvantage of can opener techniques for anterior capsulotomy is that unintended extension of the tears between scores can occur to form eccentric radial tears. These radial tears have been shown to result in asymmetric forces upon capsular contraction during healing. These asymmetric forces can result in decentration of an implanted IOL in the direction of the radial tear.
An improvement on can opener techniques for anterior capsulotomy is the continuous tear capsulotomy technique. This technique requires that the surgeon continuously tear the opening in the capsule. The technique results in a smooth non-serrated capsulotomy margin which is quite resistant to unplanned radial tears. However, the technique requires great skill, and the average ophthalmic surgeon is not likely to master the technique without extensive training and experience.
Briefly the present invention provides a laser surgery apparatus, comprising a probe that has a member comprising a reflecting surface that is transparent to visible light for reflecting laser light that is preferably invisible. The member preferably comprises a rod having a circular cross section and has an index of refraction selected such that the surface reflects the laser light by total internal reflection. In an especially preferred embodiment of the apparatus, the member is elongate and has a longitudinal axis, with the reflecting surface being disposed to reflect laser light propagating along the longitudinal axis such that the reflected light propagates along an output axis which is generally perpendicular to the longitudinal axis. The surface is preferably uncoated and is oriented to reflect an incoming light beam in a direction generally perpendicular to the direction of the incoming beam. In a preferred form of the apparatus, the surface is formed on an end of a sapphire rod which is generally wedge-shaped.
In another aspect of the present invention, there is provided an optical apparatus for a laser surgical probe which receives a laser light beam along a longitudinal axis. The optical apparatus comprises a transparent reflecting surface which redirects the light beam at an angle to the longitudinal axis, and a collimator for collimating the light beam such that light incident on the reflecting surface is collimated, preferably before it has been redirected by the reflecting surface. The reflecting surface is preferably at an angle relative to the longitudinal axis at least as great as the critical angle for total internal reflection of the laser light. The reflecting surface preferably lies on a rod of dielectric material. Light is preferably delivered via an optical fiber, with the collimator comprising a sapphire microball having its center at the focal distance from the proximal end of the fiber. The optical apparatus preferably also includes a disposable, single-use optical fiber, preferably flouride-based, having a proximal end a distal end. The optical apparatus is preferably removable from the probe so as to expose the distal end of said fiber.
In still another aspect of the present invention, there is provided a laser surgical probe, comprising a flexible waveguide for directing a laser light beam along a longitudinal axis, a rod which receives the laser light beam along the longitudinal axis, the rod having a wedge at its distal end for manipulation of tissue, and a transparent reflecting surface, the reflecting surface serving to redirect the laser light beam at an angle relative to the longitudinal axis. The probe preferably has an output surface on the rod where the light beam exits the rod, and also has a housing with the wedge extending distally beyond the housing. The reflecting surface is at an angle relative to the longitudinal axis at least as great as the critical angle required for total internal reflection of the laser light.